How do a put a movie over a rotating cube?
This is mildly tricky but because it is a cube, not terribly difficult.
You need to UV Map the cube so that each face is a separate UV &quot;island&quot;.
Select the cube
Enter edit mode
Select all.
The use the edge menu to 'mark seam' all of the seams.  You bring up the edge menu by typing CTRL-E[![Marking all the edges as seams][1]][1]
Now create a shader for the cube by going to Material Properties and clicking the '+' sign.
In the shader editor window you will have a new shader that consists of only the principled shader.
Add an image texture node.
[![added an image texture node][2]][2]
connect its color to the shader's color input
connect its alpha to the shader's alpha, as shown.
Click the file icon and select your movie.  In my example I picked an mp3.
Set the file type to movie
Set the number of frames to the number of frames in the movie.
Now comes the 'fun' part.  Your movie won't have the same aspect ratio as a cube.  So you need to unwrap and position the cube's faces one at a time.  Here's how.
Open a UV editor window and a 3D window.  (In 2.9 you can go to the &quot;UV Editing Tab&quot;
In the drop down window of UV editor, select your movie[![selecting a movie][3]][3]
In the 3d view select the cube and go into edit mode.  Select one face of the cube.
Type UU.  The first U will bring up a menu: [![unwrapping menu][4]][4]
The second U selects the first entry &quot;unwrap&quot;
Now a square will appear on your movie[![The unwrapped face.][5]][5]
You need to do this for each of the six faces.  You may need to move and rotate the squares in the UV editor to get the movie in the orientation you want.
[1]: https://i.stack.imgur.com/iqcYq.png
[2]: https://i.stack.imgur.com/rUcYY.png
[3]: https://i.stack.imgur.com/425j8.png
[4]: https://i.stack.imgur.com/m3xDd.png
[5]: https://i.stack.imgur.com/iTDqV.png